The puropose of this project is to investigate the affect of cardiac failure on cardiac valve function. In particular the relationship between cardiac mechanical function and mitral and aortic valve function and motion will be examined. The motion of the cardiac valves will be studied by using a high speed cineradiographic system to record the motion of the valve leaflets which have been coated with a thin film of a viscous radiopaque agent. Ventricular mechanical function will be quantified by using biplane ventriculography. Cardiac failure will be produced by decreasing the ventricular inotropic state (through administration of halothane) by increasing ventricular preload (through infusion of dextran) and by increasing afterload (through infusion of methoxamine). With this information we can investigate 1) The affect of heart failure on valve function, 2) The relationship between ventricular mechanical function and valve function. 3) The ability to quantify ventricular function by using parameters of valve function, 4) The affect of sodium nitroprusside on valve function in animals already in heart failure. The information gathered will aid in the understanding of the disease process associated with heart failure and will aid in use of ultrasonic recordings of valve motion in evaluating ventricular function in heart failure.